Impact of reduced cerebral perfusion pressure on outcome after severe traumatic brain injury is dependent on brain tissue oxygen pressure

INTRODUCTION. Reduced cerebral perfusion pressure (CPP) may worsen secondary damage and outcome after severe traumatic brain injury (TBI), however the optimal management of CPP is still debated. STUDY HYPOTHESIS: We hypothesized that the impact of CPP on outcome is related to brain tissue oxygen tension (PbtO2) level and that reduced CPP may worsen TBI prognosis when it is associated with brain hypoxia. DESIGN. Retrospective analysis of prospective database. METHODS. We analyzed 103 patients with severe TBI who underwent continuous PbtO2 and CPP monitoring for an average of 5 days. For each patient, duration of reduced CPP (\60 mm Hg) and brain hypoxia (PbtO2\15 mm Hg for[30 min [1]) was calculated with linear interpolation method and the relationship between CPP and PbtO2 was analyzed with Pearson's linear correlation coefficient. Outcome at 30 days was assessed with the Glasgow Outcome Score (GOS), dichotomized as good (GOS 4-5) versus poor (GOS 1-3). Multivariable associations with outcome were analyzed with stepwise forward logistic regression. RESULTS. Reduced CPP (n=790 episodes; mean duration 10.2 ± 12.3 h) was observed in 75 (74%) patients and was frequently associated with brain hypoxia (46/75; 61%). Episodes where reduced CPP were associated with normal brain oxygen did not differ significantly between patients with poor versus those with good outcome (8.2 ± 8.3 vs. 6.5 ± 9.7 h; P=0.35). In contrast, time where reduced CPP occurred simultaneously with brain hypoxia was longer in patients with poor than in those with good outcome (3.3±7.4 vs. 0.8±2.3 h; P=0.02). Outcome was significantly worse in patients who had both reduced CPP and brain hypoxia (61% had GOS 1-3 vs. 17% in those with reduced CPP but no brain hypoxia; P\0.01). Patients in whom a positive CPP-PbtO2 correlation (r[0.3) was found also were more likely to have poor outcome (69 vs. 31% in patients with no CPP-PbtO2 correlation; P\0.01). Brain hypoxia was an independent risk factor of poor prognosis (odds ratio for favorable outcome of 0.89 [95% CI 0.79-1.00] per hour spent with a PbtO2\15 mm Hg; P=0.05, adjusted for CPP, age, GCS, Marshall CT and APACHE II). CONCLUSIONS. Low CPP may significantly worsen outcome after severe TBI when it is associated with brain tissue hypoxia. PbtO2-targeted management of CPP may optimize TBI therapy and improve outcome of head-injured patients.

Ecstasy can cause brain damage

This poster informs about the dangers of Ecstasy stating: 'Medical research proves that Ecstasy can cause brain damage. Deny it all you like, but you know it won't wash'.

Unintentional injuries among 16 to 20 year old students in Switzerland.

In our society, accidents constitute a major public health problem, especially among youth. The objective of this paper was to describe the incidence of nonfatal injuries that required medical care among 16 to 20 year-old in Switzerland, its distribution by type of injury and whether there were differences by gender or by academic track and whether these injuries had sequels (hospitalisation, physical and psychological sequels). Overall, 28.3% of the sample reported at least one accident needing medical care in the previous 12 months, with males having more accidents than females and apprentices more than students. By type of accident, sports were the most frequently reported, followed by traffic, leisure time and work accidents. Half of males and one-third of females reported more than one accident, and 16% and 8% of them, respectively, reported four or more. Both physical and psychological sequels were more frequent among females, while hospitalisation was more frequent among males. Accident prevalence rates remain high among adolescents. Safety counselling and environmental measures need to be implemented.

Reverse the 'real brain drain' for our children, urges Director of Public Health

The second annual report of the Director of Public Health (DPH) for Northern Ireland was published today. This significant report highlights the many public health challenges that affect people in Northern Ireland. Dr Carolyn Harper, Director of Public Health, leads the public health team that tackles this complex agenda, working with many statutory, community and voluntary partner organisations across health, local government, education, housing and other sectors.

Reducing unintentional injuries in and around the home among children under 5 Years

Public Health England today launches 2 new resources for local authorities on preventing accidents to children and young people in the home and on the road. The reports show whilst the number of children and young people killed or seriously injured continues to fall in England there are still significant numbers of deaths and emergency admissions from preventable causes. On average each year between 2008 to 2012, 525 children and young people under 25 died and there were more than 53,700 admissions to hospital. The reports highlight actions local partners can take to reduce accidents including improving safety for children travelling to and from school and using existing services like health visitors and children’s centres. The Reducing unintentional injuries in and around the home among children under 5 Years and the Reducing unintentional injuries on the roads among children and young people under 25 reports include an analysis of data between 2008 to 2012. Key findings from the reports include: home injuries (under 5 years of age): an average of 62 children died each year between 2008 and 2012 these injuries result in an estimated 40,000 emergency hospital admissions among children of this age each year 5 injury types should be prioritised for the under-fives: choking; suffocation and strangulation; falls; poisoning; burns and scalds; and drowning hospital admission rate for unintentional injuries among the under-fives is 45% higher for children from the most deprived areas compared with children from the least deprived Road traffic injuries (under 25 years of age) there were 2,316 deaths recorded by the police among road users under the age of 25 years, an average of 463 under 25s each year there were 68,657 admissions to hospital as a result of road traffic injuries, an average of 13,731 each year in total there were 322,613 casualties of all severities recorded by the police, an average of 64,523 each year the rate of fatal and serious injuries for 10to 14 year olds was significantly greater for children from the 20% most deprived areas (37 per 100,000) compared with those from the most affluent areas (10 per 100,000)

Reducing unintentional injuries on the roads among children and young people under 25

Public Health England today launches 2 new resources for local authorities on preventing accidents to children and young people in the home and on the road. The reports show whilst the number of children and young people killed or seriously injured continues to fall in England there are still significant numbers of deaths and emergency admissions from preventable causes. On average each year between 2008 to 2012, 525 children and young people under 25 died and there were more than 53,700 admissions to hospital. The reports highlight actions local partners can take to reduce accidents including improving safety for children travelling to and from school and using existing services like health visitors and children’s centres. The Reducing unintentional injuries in and around the home among children under 5 Years and the Reducing unintentional injuries on the roads among children and young people under 25 reports include an analysis of data between 2008 to 2012. Key findings from the reports include: home injuries (under 5 years of age): an average of 62 children died each year between 2008 and 2012 these injuries result in an estimated 40,000 emergency hospital admissions among children of this age each year 5 injury types should be prioritised for the under-fives: choking; suffocation and strangulation; falls; poisoning; burns and scalds; and drowning hospital admission rate for unintentional injuries among the under-fives is 45% higher for children from the most deprived areas compared with children from the least deprived Road traffic injuries (under 25 years of age) there were 2,316 deaths recorded by the police among road users under the age of 25 years, an average of 463 under 25s each year there were 68,657 admissions to hospital as a result of road traffic injuries, an average of 13,731 each year in total there were 322,613 casualties of all severities recorded by the police, an average of 64,523 each year the rate of fatal and serious injuries for 10to 14 year olds was significantly greater for children from the 20% most deprived areas (37 per 100,000) compared with those from the most affluent areas (10 per 100,000)

Sensing of glucose in the brain.

The brain, and in particular the hypothalamus and brainstem, have been recognized for decades as important centers for the homeostatic control of feeding, energy expenditure, and glucose homeostasis. These structures contain neurons and neuronal circuits that may be directly or indirectly activated or inhibited by glucose, lipids, or amino acids. The detection by neurons of these nutrient cues may become deregulated, and possibly cause metabolic diseases such as obesity and diabetes. Thus, there is a major interest in identifying these neurons, how they respond to nutrients, the neuronal circuits they form, and the physiological function they control. Here I will review some aspects of glucose sensing by the brain. The brain is responsive to both hyperglycemia and hypoglycemia, and the glucose sensing cells involved are distributed in several anatomical sites that are connected to each other. These eventually control the activity of the sympathetic or parasympathetic nervous system, which regulates the function of peripheral organs such as liver, white and brown fat, muscle, and pancreatic islets alpha and beta cells. There is now evidence for an extreme diversity in the sensing mechanisms used, and these will be reviewed.

How local excitation-inhibition ratio impacts the whole brain dynamics.

The spontaneous activity of the brain shows different features at different scales. On one hand, neuroimaging studies show that long-range correlations are highly structured in spatiotemporal patterns, known as resting-state networks, on the other hand, neurophysiological reports show that short-range correlations between neighboring neurons are low, despite a large amount of shared presynaptic inputs. Different dynamical mechanisms of local decorrelation have been proposed, among which is feedback inhibition. Here, we investigated the effect of locally regulating the feedback inhibition on the global dynamics of a large-scale brain model, in which the long-range connections are given by diffusion imaging data of human subjects. We used simulations and analytical methods to show that locally constraining the feedback inhibition to compensate for the excess of long-range excitatory connectivity, to preserve the asynchronous state, crucially changes the characteristics of the emergent resting and evoked activity. First, it significantly improves the model's prediction of the empirical human functional connectivity. Second, relaxing this constraint leads to an unrealistic network evoked activity, with systematic coactivation of cortical areas which are components of the default-mode network, whereas regulation of feedback inhibition prevents this. Finally, information theoretic analysis shows that regulation of the local feedback inhibition increases both the entropy and the Fisher information of the network evoked responses. Hence, it enhances the information capacity and the discrimination accuracy of the global network. In conclusion, the local excitation-inhibition ratio impacts the structure of the spontaneous activity and the information transmission at the large-scale brain level.

Brain natriuretic peptide and left ventricular dysfunction in chagasic cardiomyopathy

Global left ventricular (LV) systolic dysfunction is the strongest predictor of morbidity and mortality in Chagas disease. Echocardiography is considered the gold standard for the detection of LV dysfunction, but not always available in endemic areas where chagasic cardiomyopathy is most common. Brain natriuretic peptide (BNP) is a neurohormone that has been recently described as a simple and inexpensive diagnostic and prognostic marker for patients with congestive heart failure. Chagasic patients (n = 63) and non-infected healthy individuals (n = 18) were recruited prospectively and underwent complete clinical examination, echocardiography and 24-h Holter monitoring. BNP was measured from thawed plasma samples using the Triage BNP test. We observed high levels of BNP in association with depression of LV ejection fraction, with increase of LV end-diastolic diameter and with LV premature complexes. An elevated concentration of BNP, defined as a concentration of 60 pg/ml or more, had a sensitivity of 91.7%, specificity of 82.8%, positive predictive value of 52.4%, and negative predictive value of 98% for detecting LV dysfunction (LV ejection fraction < 40%).BNP measurement using a simple, relatively inexpensive and rapid test has a promising role in identifying LV dysfunction associated with chagasic cardiomyopathy. Equally important, patients with Trypanosoma cruzi infection who have low levels of BNP level in plasma have a very low likelihood of severe cardiac involvement, and echocardiography is probably not necessary.

Brain aging in the oldest-old.

Nonagenarians and centenarians represent a quickly growing age group worldwide. In parallel, the prevalence of dementia increases substantially, but how to define dementia in this oldest-old age segment remains unclear. Although the idea that the risk of Alzheimer's disease (AD) decreases after age 90 has now been questioned, the oldest-old still represent a population relatively resistant to degenerative brain processes. Brain aging is characterised by the formation of neurofibrillary tangles (NFTs) and senile plaques (SPs) as well as neuronal and synaptic loss in both cognitively intact individuals and patients with AD. In nondemented cases NFTs are usually restricted to the hippocampal formation, whereas the progressive involvement of the association areas in the temporal neocortex parallels the development of overt clinical signs of dementia. In contrast, there is little correlation between the quantitative distribution of SP and AD severity. The pattern of lesion distribution and neuronal loss changes in extreme aging relative to the younger-old. In contrast to younger cases where dementia is mainly related to severe NFT formation within adjacent components of the medial and inferior aspects of the temporal cortex, oldest-old individuals display a preferential involvement of the anterior part of the CA1 field of the hippocampus whereas the inferior temporal and frontal association areas are relatively spared. This pattern suggests that both the extent of NFT development in the hippocampus as well as a displacement of subregional NFT distribution within the Cornu ammonis (CA) fields may be key determinants of dementia in the very old. Cortical association areas are relatively preserved. The progression of NFT formation across increasing cognitive impairment was significantly slower in nonagenarians and centenarians compared to younger cases in the CA1 field and entorhinal cortex. The total amount of amyloid and the neuronal loss in these regions were also significantly lower than those reported in younger AD cases. Overall, there is evidence that pathological substrates of cognitive deterioration in the oldest-old are different from those observed in the younger-old. Microvascular parameters such as mean capillary diameters may be key factors to consider for the prediction of cognitive decline in the oldest-old. Neuropathological particularities of the oldest-old may be related to "longevity-enabling" genes although little or nothing is known in this promising field of future research.

Protein kinase C-activating tumor promoters enhance the differentiation of astrocytes in aggregating fetal brain cell cultures.

Serum-free aggregating cell cultures of fetal rat telencephalon treated with the potent tumor promoter phorbol 12-myristate 13-acetate (PMA) showed a marked, rapid, and sustained increase in the activity of the astrocyte-specific enzyme glutamine synthetase (GS). This effect was accompanied by a small increase in RNA synthesis and a progressive reduction in DNA synthesis. Only mitotically active cultures were responsive to PMA treatments. Since in aggregate cultures astrocytes are the preponderant cell type, both in number and mitotic activity, it can be concluded that PMA induces and/or enhances the terminal differentiation of astrocytes. The developmental expression of GS was also greatly stimulated by mezerein, a potent nonphorbol tumor promoter, but not by 4 alpha-phorbol 12,13-didecanoate, a nonpromoting phorbol ester. Since both tumor promoters, PMA and mezerein, are potent and specific activators of C-kinase, it is suggested that C-kinase plays a regulatory role in the growth and differentiation of normal astrocytes.

The pattern and Loci of training-induced brain changes in healthy older adults are predicted by the nature of the intervention.

There is enormous interest in designing training methods for reducing cognitive decline in healthy older adults. Because it is impaired with aging, multitasking has often been targeted and has been shown to be malleable with appropriate training. Investigating the effects of cognitive training on functional brain activation might provide critical indication regarding the mechanisms that underlie those positive effects, as well as provide models for selecting appropriate training methods. The few studies that have looked at brain correlates of cognitive training indicate a variable pattern and location of brain changes - a result that might relate to differences in training formats. The goal of this study was to measure the neural substrates as a function of whether divided attentional training programs induced the use of alternative processes or whether it relied on repeated practice. Forty-eight older adults were randomly allocated to one of three training programs. In the SINGLE REPEATED training, participants practiced an alphanumeric equation and a visual detection task, each under focused attention. In the DIVIDED FIXED training, participants practiced combining verification and detection by divided attention, with equal attention allocated to both tasks. In the DIVIDED VARIABLE training, participants completed the task by divided attention, but were taught to vary the attentional priority allocated to each task. Brain activation was measured with fMRI pre- and post-training while completing each task individually and the two tasks combined. The three training programs resulted in markedly different brain changes. Practice on individual tasks in the SINGLE REPEATED training resulted in reduced brain activation whereas DIVIDED VARIABLE training resulted in a larger recruitment of the right superior and middle frontal gyrus, a region that has been involved in multitasking. The type of training is a critical factor in determining the pattern of brain activation.

Cerebral extracellular lactate increase is predominantly nonischemic in patients with severe traumatic brain injury.

Growing evidence suggests that endogenous lactate is an important substrate for neurons. This study aimed to examine cerebral lactate metabolism and its relationship with brain perfusion in patients with severe traumatic brain injury (TBI). A prospective cohort of 24 patients with severe TBI monitored with cerebral microdialysis (CMD) and brain tissue oxygen tension (PbtO2) was studied. Brain lactate metabolism was assessed by quantification of elevated CMD lactate samples (>4 mmol/L); these were matched to CMD pyruvate and PbtO2 values and dichotomized as glycolytic (CMD pyruvate >119 μmol/L vs. low pyruvate) and hypoxic (PbtO2 <20 mm Hg vs. nonhypoxic). Using perfusion computed tomography (CT), brain perfusion was categorized as oligemic, normal, or hyperemic, and was compared with CMD and PbtO2 data. Samples with elevated CMD lactate were frequently observed (41±8%), and we found that brain lactate elevations were predominantly associated with glycolysis and normal PbtO2 (73±8%) rather than brain hypoxia (14±6%). Furthermore, glycolytic lactate was always associated with normal or hyperemic brain perfusion, whereas all episodes with hypoxic lactate were associated with diffuse oligemia. Our findings suggest predominant nonischemic cerebral extracellular lactate release after TBI and support the concept that lactate may be used as an energy substrate by the injured human brain.

Prevalence of injuries among three-year-old children in the Republic of Ireland in 2011

The Institute of Public health in Ireland (IPH) produces population prevalence estimates and forecasts for a number of chronic conditions among adults. IPH has now applied the methodology to examine health conditions and injuries among young children across the island of Ireland.This short report is a supplement to a previous IPH report that examines health conditions among three-year-olds in the Republic of Ireland. It provides estimates of the prevalence of injuries that required hospital admission or treatment among three-year-olds in the Republic of Ireland in 2011. The analysis identifies risk factors associated with child injuries and provides estimates of the prevalence of these conditions for each of the 34 administrative cities and counties.